Powered air cleaning system and air cleaning method

ABSTRACT

A powered air cleaning system ( 1 ) and air cleaning method are disclosed. The system comprises a flow path ( 22 ) extending through the system from an air inlet ( 4 ) to a clean air outlet ( 5 ). A motor-driven fan ( 24 ) located along the flow path draws particulate debris laden air into the inlet and rotates it about an axis (A-A) to form a rotating flow that stratifies the debris laden air with the heaviest particles in the outermost orbits of the rotating flow. An ejector port ( 25 ) is provided for ejecting particulate debris laden air from the stratified rotating flow in the system to the environment. An air filter ( 9 ) located within the rotating flow and across the flow path upstream of the outlet filters air from the innermost orbits of the stratified rotating flow. The motor-driven fan is operated to maintain a positive air pressure in the system on the filter even with cyclic air flow demands so that the rotating air flow continually sweeps the outside surface of the air filter to minimize buildup of debris on the filter.

TECHNICAL FIELD

[0001] The present invention is directed to an improved powered,atmospheric ejective, air cleaning system and air cleaning method forefficiently removing debris from debris laden air to supply clean air toa device with which the system is used. For example, the invention isuseful in connection with total air flow applications such asventilation systems, as a fixed air flow provider for heat exchangersand heating and air conditioning systems, and with devices having avariable air flow demand, particularly internal combustion engines whichexert a variable vacuum on their air intake to be supplied with cleanair.

BACKGROUND AND SUMMARY

[0002] Air intakes that centrifugally separate heavier-than-airparticles from the air to be used in internal combustion engines,ventilation systems, and other apparatus that draw in air laden withdebris, are known. The use of in-line filters in air delivery systems toclean the air is also, per se, known. However, air filters are subjectto plugging by debris from the air passing through the filter, whicheventually increases the restriction to air flow through the filter anddecreases the operating performance of an associated device, such as anelectronically controlled internal combustion engine being supplied withair through the filter. Frequent filter replacement and shorter serviceintervals may also be required, which increases the cost of operation.There is a need for an improved air cleaning system and air cleaningmethod which combine centrifugal separation and air filtration in amanner to efficiently remove debris from debris laden air while reducingor avoiding the aforementioned problems.

[0003] A powered air cleaning system according to the inventioncomprises a flow path extending through the system from an air inlet toa clean air outlet. A motor-driven fan is located along the flow path todraw particulate debris laden air into the inlet and rotate it about anaxis to form a rotating flow that stratifies the debris laden air withthe heaviest particles in the outermost orbits of the rotating flow. Anejector port is provided for ejecting particulate debris laden air fromthe stratified rotating flow in the system to the environment. An airfilter is located within the rotating flow and across the flow pathupstream of the clean air outlet for filtering air from the innermostorbits of the stratified rotating flow. According to the disclosedexample embodiment of this invention, the filter is elongated in thedirection of the axis about which the debris laden air is rotated. Anouter peripheral surface of the filter within the rotating flow is sweptby innermost orbits of the stratified rotating flow for minimizingdebris buildup on the filter.

[0004] An air cleaning method of the invention comprises drawingparticulate debris laden air into the air cleaning system with themotor-driven fan located in the system, forming a rotating flow of thedebris laden air in the system to stratify the flow with the heaviestparticles in the outermost orbits of the rotating flow, flowing air fromthe innermost orbits of the rotating flow through the filter enroute tothe outlet of the system, and returning particulate debris laden airfrom the stratified rotating flow in the system to the environment.According to the example embodiment air is supplied to a device with avariable air flow demand, which applies a variable vacuum to the outletof the air cleaning system, and the method further includes operatingthe motor-driven fan to maintain positive air flow pressure in thesystem to return particulate debris laden air to the environment fromthe system at all rates of air flow demand by the device. The positiveair flow pressure, acting on the filter of the system located within therotating flow, keeps debris buildup on the filter to a minimum.Accordingly, the system self-cleans its air filter.

[0005] These and other features and advantages of the present inventionwill become more apparent from the following description when taken inconnection with the accompanying drawings, which show, for purposes ofillustration only, one preferred embodiment in accordance with thepresent invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006]FIG. 1 is a perspective view from the front, inlet end, and to oneside, of a powered air cleaning system/apparatus according to one,preferred embodiment of the present invention.

[0007]FIG. 2 is a perspective view from the back, outlet end, and to oneside, of the air cleaning system of FIG. 1, shown, schematically,connected to an air intake of a device with a variable air flow demand.

[0008]FIG. 3 is a view of the system similar to FIG. 1 with portions ofthe housing cut away to show components within the housing.

[0009]FIG. 4 is a view of the system similar to FIG. 2 with portions ofthe housing cut away to depict components inside the housing.

[0010]FIG. 5 is a view of the system like FIG. 1 except with a portionof the housing removed and with the filter in the system removed to showthe clean air outlet orifice through the back, outlet end of thehousing.

[0011]FIG. 6 is a perspective view of the system like FIG. 1 but withthe detachable motorized fan housing and filter housing forming thesystem housing being separated from one another.

[0012]FIG. 7 is a detailed view of a portion of the joined detachablemotorized fan housing and filter housing having a removable joining clipthereof as shown in FIG. 5.

[0013]FIG. 8 is a perspective view from the front, inlet end, and to oneside, of the detachable motorized fan housing of the system of FIG. 1.

[0014]FIG. 9 is a perspective view from the back, outlet end of thedetachable motorized fan housing system of FIG. 1.

[0015]FIG. 10 is a perspective view of a main primary air filer elementused in the system of FIG. 1.

[0016]FIG. 11 is a perspective view of a secondary safety air filterelement optionally used in the system of FIG. 1 inside of the mainprimary air filter element.

[0017]FIG. 12 is a perspective view of the filter housing from the frontend with no filter installed therein.

[0018]FIG. 13 is a perspective view of the filter housing from the back,outlet end thereof with no filter installed.

[0019]FIG. 14 is a perspective view of the filter housing like FIG. 12but with the optional safety filter installed.

[0020]FIG. 15 is a perspective view of the filter housing like FIG. 13but with the main filter shown installed therein.

BEST MODE FOR CARRYING OUT THE INVENTION

[0021] Referring now to the drawings, a powered air cleaning system orapparatus 1, FIGS. 1-6, according to the example embodiment is shownconnected to the air intake 29 of a device 28, such as an internalcombustion engine or other device requiring a supply of clean air, asshown schematically in FIG. 2. The system comprises a flow path 22extending through the system from an air inlet 4 to a clean air outlet 5which supplies clean air to the air intake 29 of device 28. The flowpath is located within a generally cylindrical housing 23 of the system.Housing 23 is formed by two detachable components—motorized fan housing2 and filter housing 3 which are detachably connected to one another ata service flange assembly 6 by joining clips 7, see FIG. 7. For thispurpose each of the housings 2 and 3 has a joining flange, 16 and 17,respectively. The housings 2 and 3 are shown detached from one anotherin FIG. 6 and shown separately in FIGS. 8 and 9, and 12 and 13,respectively.

[0022] A motor-driven fan 24, comprising a fan blade 10 mounted on theoutput shaft of an electric motor 13, is located along the flow path 22to draw particulate debris laden air into the inlet 4 and rotate itabout an axis A-A to form a rotating flow in the system that stratifiesthe debris laden air with the heaviest particles in the outermost orbitsof the rotating flow. A compression assembly 11 in the form of an angledlouver/motor mount assembly with fixed louvers or vanes 12 is locatedwithin the fan housing 2 downstream of the fan blade 10. The compressionassembly compresses the volume of the rotating flow of debris laden airdrawn into the system inlet to increase the air velocity and centrifugalforce acting on the airborne articles. The motor-driven fan 24 issupported at motor 13 thereof within the fan housing by way of the anglelouver/motor mount assembly 11 as seen in FIGS. 3, 4, 8 and 9.

[0023] A separator-ejector chamber 18 is provided in the flow path ofthe air cleaning system downstream of the angled louver/motor mountassembly, FIGS. 3-6, 9 and 15. The outermost orbits of the rotating flowpattern of debris laden air ride on the outer wall 27 of theseparator-ejector chamber until reaching an annular ejector port 25formed about the outlet 5 in the outlet end of the housing radiallyoutward of the clean air outlet. The ejector port is formed by a seriesof circumferential radial ejection slots 8 separated by strakes 15. Theejector port ejects particulate debris laden air from the stratifiedrotating flow in the system to the environment.

[0024] An air filter 9, FIGS. 2-4, 6 and 15, in the form of a filterpackage of at least a main primary air filter element 20, FIGS. 10 and15, and optionally a secondary safety air filter element 21, FIGS. 11and 14, located within the filter element 20, is located within therotating flow and across the flow path upstream of the outlet forfiltering air from the innermost orbits of the stratified rotating flowin the system as the air flows to the clean air outlet 5. The filter 9is elongated in the direction of and extends along the centrallongitudinal axis A-A of the generally cylindrical housing 23 in theseparator-ejector chamber from the outlet end, where it is mounted onclean air outlet orifice 19, FIG. 5. The upstream end of the filter 9 issupported by a filter compression bracket 14 connected to a supportflange 30, FIG. 9, on the end of motor 13.

[0025] Debris buildup on the outer surface of the filter 9 is minimizedby locating the filter within the rotating flow of the debris laden airin the separator-ejector chamber 18 and by returning particulate debrisladen air from the stratified rotating flow in chamber 18 unrestrictedthrough the ejector port 25 at the end of the chamber, e.g., withoutdisrupting the stratified rotating flow in the chamber. The selfcleaning action on the filter 9 has also been found to be enhanced, insupplying air to the air intake 29 of a device 28 having a cyclic airflow demand, such as an internal combustion engine which applies avariable vacuum to the outlet 5 of the system, by operating themotor-driven fan to maintain positive air flow pressure on the outersurface of the filter and to return debris laden air to the environmentfrom the system at all rates of air flow demanded by the device. The aircleaning system 1 is designed to generate a much larger air flow thanthe engine or apparatus 28 upon which it is installed requires, therebyproviding a consistent positive air flow pressure to the filter keepingdebris buildup on the air filter to a minimum and providing a powerfulair flow out of the 360° ejection port 25 formed by the series of radialejection slots 8 located at the end of the separator-ejector chamber.

[0026] The air cleaning system and air cleaning method of the inventionmake it possible to maintain low air filter restriction throughoutnormal service intervals for internal combustion engines and otherapparatus by significantly extending air filter life over currentservice intervals. While the air cleaning system and air cleaning methodhave been described specifically for use in supplying clean air to aninternal combustion engine, the invention is not limited to such a usebut has wide application for a variety of devices requiring a supply ofclean air including ventilation systems, heat exchangers, aircompressors, and heating and air conditioning systems.

[0027] While we have shown and described only one embodiment inaccordance with the present invention, it is understood that the same isnot limited thereto, but is susceptible to numerous changes andmodifications as known to the skilled in the art. For example, thepowered air cleaning system of the invention can be used without the airfilter 9 to supply air to a device where centrifugal separation ofdebris from debris laden air and withdrawal of air from the innermostorbits of the rotating flow in the system by a vacuum from the device atthe outlet of the system provides satisfactory cleaning. In this regard,it is noted that the positive pressure in the device maintains flowthrough the ejector port of the system while the pressure at the cleanair outlet remains essentially neutral, with or without air filter 9.The device draws clean air from the clean air outlet in accordance withits demand, e.g., vacuum pull applied to the clean air outlet of thesystem. Therefore, we do not wish to be limited to the details shown anddescribed herein, but instead to cover all such changes andmodifications as are encompassed by the scope of the appended claims.

What is claimed is:
 1. A powered air cleaning system comprising: a flowpath extending through the system from an inlet to an outlet; amotor-driven fan located along the flow path to draw particulate debrisladen air into the inlet and rotate it about an axis to form a rotatingflow that stratifies the debris laden air with the heaviest particles inthe outermost orbits of the rotating flow; an ejector port for ejectingparticulate debris laden air from the stratified rotating flow in thesystem to the environment; and an air filter located within the rotatingflow and across the flow path upstream of the outlet for filtering airfrom the innermost orbits of the stratified rotating flow.
 2. The aircleaning system according to claim 1, wherein the filter is elongated inthe direction of the axis about which the debris laden air is rotated.3. The air cleaning system according to claim 2, wherein an outerperipheral surface of the elongated filter is cylindrical.
 4. The aircleaning system according to claim 1, further comprising a compressionassembly for compressing the volume of the rotating flow of debris ladenair to increase the air velocity and centrifugal force acting on theairborne particles.
 5. The air cleaning system according to claim 4,wherein the compression assembly provides support for the motor-drivenfan.
 6. The air cleaning system according to claim 4, wherein thecompression assembly includes a plurality of stationary vanes in theflow path.
 7. The air cleaning system according to claim 4, furthercomprising a separator-ejector chamber in the flow path downstream ofthe compression assembly, the outermost orbits of the rotating flowriding on an outer wall of the separator-ejector chamber until reachingsaid ejector port.
 8. The air cleaning system according to claim 7,wherein said filter is located centrally within said separator-ejectorchamber.
 9. The air cleaning system according to claim 1, furthercomprising a generally cylindrical housing, said inlet and said outletbeing arranged at respective ends of said housing and said flow pathextending through housing.
 10. The air cleaning system according toclaim 9, wherein said ejector port is arranged in the outlet end of thehousing radially outward from said outlet.
 11. The air cleaning systemaccording to claim 9, wherein said filter extends along a centrallongitudinal axis of the generally cylindrical housing from the outletend thereof.
 12. The air cleaning system according to claim 11, furthercomprising a bracket for supporting within the housing an end of thefilter remote from the outlet end of the housing.
 13. A powered aircleaning system for use with a device having a variable air flow demand,the system comprising: a flow path extending through the system from aninlet to an outlet for supplying air to the device; a motor-driven fanlocated along the flow path to draw particulate debris laden air intothe inlet and rotate it about an axis to form a rotating flow thatstratifies the debris laden air with the heaviest particles in theoutermost orbits of the rotating flow; an ejector port for ejectingparticulate debris laden air from the stratified rotating flow in thesystem to the environment; an air filter located within the rotatingflow and across the flow path upstream of the outlet for filtering airfrom the innermost orbits of the stratified rotating flow; wherein themotor-driven fan is operable to maintain positive air flow pressure toeject debris laden air from the stratified rotating flow in the systemto the environment at all rates of air flow demanded by the device. 14.A powered air cleaning system for use with a device having a variableair flow demand, the system comprising: a flow path extending throughthe system from an inlet to an outlet for supplying air to the device; amotor-driven fan located along the flow path to draw particulate debrisladen air into the inlet and rotate it about an axis to form a rotatingflow that stratifies the debris laden air with the heaviest particles inthe outermost orbits of the rotating flow; an ejector port for ejectingparticulate debris laden air from the stratified rotating flow In thesystem to the environment; an air filter located within the rotatingflow and across the flow path upstream of the outlet for filtering airfrom the innermost orbits of the stratified rotating flow, wherein themotor-driven fan is operable to maintain positive air flow pressure atall rates of air flow demand by the device to minimize debris buildup onthe filter.
 15. The air cleaning system according to claim 14, whereinthe device with a variable air flow demand is an internal combustionengine which exerts a variable vacuum on the outlet of the system by wayof the air intake of the engine.
 16. An air cleaning method comprising:drawing particulate debris laden air into an air cleaning system with amotor-driven fan located in the system; forming a rotating flow of thedebris laden air in the system to stratify the flow with the heaviestparticles in the outermost orbits of the rotating flow, flowing air fromthe innermost orbits of the rotating flow through a filter locatedwithin the rotating flow to provide a self cleaning action on the filterby the air enroute to an outlet of the system; and returning particulatedebris laden air from the stratified rotating flow in the system to theenvironment.
 17. (cancelled)
 18. The method according to claim 16,wherein said returning is performed without disrupting the stratifiedrotating flow in the system.
 19. The method according to claim 18,wherein said returning includes flowing stratified rotating flowunrestricted through an ejector port of the system to the environment.20. The method according to claim 16 for use in supplying air to adevice with a variable air flow demand which applies a variable vacuumto the outlet of the air cleaning system, the method further includingoperating the motor-driven fan to maintain positive air flow pressure toreturn particulate debris laden air to the environment from the systemat all rates of air flow demand by the device to allow buildup of debrison the filter to be removed at least during low rates of air flowdemand.
 21. (cancelled)